Impeller blade



Oct. 25, 1960 P. L. HAIMS IMPELLER' BLADE Filed Dec. 26, 1956 INVENTOR. PHIL/P L. HA/MS BY (yyl a'nd/ aio wi His Attorneys llVIPELLER BLADE Philip L. Haims, 13394 Cedar Road, Cleveland Heights 18, Ohio Filed Dec. 26, 1956,'Ser. N0. 630,583

7 Claims. (Cl. 230259) It has been discovered that if an impeller blade is' formed with a relatively sharp leading edge and a trailing edge of substantial transverse dimension, unusual, un-

expected, and novel results are obtained. When an impeller is rotated a vacuous area is created behind each such blade trailing edge. Through the provision of a blade having a trailing edge of substantial transverse dimension a substantial vacuous area is created. It is believed that this increase in vacuous area explains the phenomenon which has been discovered.

When an impeller having blades made in accordance with this teaching is, as an example, used as an air circulator, air is drawn into the plane of rotation from 'both sides of the impeller. The air tends to be ejected .into the area surrounding the perimeter of fan blade rotation. Thus, an area of increased air pressure is created around the perimeter of fan rotation. The net result of this phenomenon is to provide an air circulator which tends to circulate and cleanse the air without causing any noticeable drafts. i

One of the principal objects of this invention is, therefore, to provide a new and improved impellerblade which utilizes the concept of creating a large vacuous area at the trailing edge of the blade to obtain a new and heretofore unknown path of air movement relative to the blade movement.

A further object of the invention is to further increase such vacuous area and at the same time provide a blade which is light weight, simple and inexpensive to manufacture through the provision of a hollow impeller blade.

Still another object of the invention is to provide a new and novel impeller blade having first and second pitch contoured blade surfaces which are relatively divergent from the leading edge of the blade to provide surfaces which tend to draw air relatively from both directions and additionally tend to enhance the vacuous area behind the trailing edge of the blade.

Another, and a more detailed object of the invention, is to provide such a new and novel hollow blade with an end closure at the blade end remote from the axis of rotation to increase and aid in the maintenance of such vacuous area.

' Still another object of the invention is to provide an impeller blade having one of the blade surfaces formed with a steep pitch and the other of the blade surfaces formed as substantially a plane surface to provide an Patented Oct. 25, 1960 ject of providing a blade with substantial lift which can be employed as a toy or the like.

I Still another object of the invention is to provide an impeller blade in which the pitch of the curved blade surface increases as one measures such pitch from the axis of rotation outwardly'toward the remote end of the impeller blade.

Other objects and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a top plan view of a four-bladed embodiment of an impeller made in accordance with the present teaching; and

Figure 2 is a side elevational view, partly in cross section, of one of the improved impellers mounted on a motor for use as anaircirculator.

Referring to the drawings and to Figure 2 in particular, a motor is shown at 10. The motor has a shaft 11.

An impeller is shown generally at 12. The impeller has a hub 13. The hub includes means for mounting the impeller which means in the embodiment shown takes the form of an aperture 14 formed in the hub 13. The shaft 11 projects through the aperture 14. A bolt 15 is providedto fix the impeller 12 to the shaft 11.

The impeller 12 has a plurality of blades 20, 2 1, Z2, 23. In the preferred and disclosed hollow form of construction, each such blade has a first pitch contoured member 25 and a second pitch contoured member 26. The first and second pitch contoured members 25, 26 have a commen and preferably sharp leading edge 27. In the disclosed and preferred hollow embodiment the pitch contou-red members 25, 26 have spaced trailing edges 28, 29 respectively.

Again, in the preferred and shown embodiment, a cavity of generally V-shaped cross section is defined in each of the impeller blades 20, 21, 22, 23. These cavities 32 may be defined in part by an end closure 30 at the ends remote from the axis of rotation, which is the axis of the shaft 11.

Alternatively, the blades as viewed in'plan may be of any of an infinite number of contour definitions. The contour, for example, maybe somewhat crescent-shaped or of any other of the prior known impeller blade plan contours. The first and second pitch contoured members 25, 26 may be formed, as in the crescent shape, to serve the function of the end closure member 30. It appears, however, that excellent results are obtained with the construction disclosed.

As can best be seen by the reference to Figure 2, the transverse dimension between the trailing edges 28, 29 increases when measured from the inward or rotational axis end of the impeller blades toward the remote end at the closure 30. Each of the impeller blade top members 25 has an outer pitch contoured surface 3-4 which is concave in cross section. This concavity increases when measured from the inner to the outer blade ends.

In this preferred embodiment, the second or bottom member has an outer pitch contoured surface which is substantially a plane surface. Thus, in any given plane of cross section, the transverse dimension of each of the blades increases from the blade leading edge 27 to the blade trailing edge defined by the member trailing edges 28, 29. Thus in any planeof blade cross section subat the blade trailing edge.

It has been discovered that when one of the blades made in accordance with the present teaching is used as an air circulator, as shown in Figure 2, unusual and unexpected results are obtained insofar as the circulation of air is concerned. When placed in a smoke-filled area the air movement seems to follow the pattern indicated by the arrows. Thus air is drawn in from both above and below the fan setting up a turbulent condition in the plane of blade rotation. Air is ultimately ejected about the periphery of the contour defined by the rotating blade. When placed in a smoke-filled area one can see the smoke being drawn into the blade but yet the air ejected at the blade perimeter bears less smoke and often no visible smoke. It is believed that the turbulent condition tends to break up and disperse the smoke particles.

The unusual air pattern provides one of the outstanding features of the invention. All the air surrounding the impeller is affected, while in more conventional fans air tends to follow a funnel-like path. The air movement caused by this improved impeller tends to reach in to the corners of a room and circulate all the air, while prior fans tend to recirculate the same portions of air in a room leaving much of the room unaffected.

Additionally, though total air movement caused by this impeller appears to be as great or greater than movement caused by prior known blades of comparable size and motivating force no noticeable drafts are felt. It is believed that this is due to the fact that the air movement assumes this new and unexpected pattern and that the movement is so divided into multiplicity of directions as to minimize drafts. Thus, an improved air circulator which tends to achieve a beneficial effect of prior known circulators without the principal deterrent of prior known circulators, namely drafts which tend to cause persons in the vicinity of such circulators to catch cold, has been provided. It further appears that air rushing into the increased vacuous areas behind the trailing edges aids in the creation of this multi directional movement.

A further discovery has been made. It has been discovered that an impeller made in accordance with this teaching forms an excellent wind mill. The trailing edge exposed to the wind provides a large surface for catching the wind. At the same time the sharp leading edge and overall design provide substantially the same resistance to rotation as prior known blades. Thus, if wind was coming from the upper left hand corner of the page the blade of Figure 1 would rotate clockwise. The trailing edge of blade 22 will more effectively catch wind than prior known blades while the leading edge of blade 20 will have little if any more resistance. Blades 21 and 23 have little or no effect when the blade is in this precise position.

There has thus been described an improved impeller having blades which create substantial vacuous areas behind the trailing edges of such blades and a blade which can be used as a draftless air circulator or as a wind mill, or as a propeller in any of the prior known applications for propellers and impellers with exceptional, improved, and novel results.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

I claim:

1. An impeller comprising, a hub having means for mounting for rotation about an axis, a plurality of blades fixed to the hub and extending longitudinally along a path generally lateral and normal to the hub axis; each such blade comprising, first and second pitch contoured members, the members having a common leading edge and spaced trailing edges, said members defining a cavity therein, said cavity being substantially equal to the total volume defined by the contoured members and being open to the ambient atmosphere through such space between said trailing edges, said cavities each extending substantially to the radial extermities of an impeller.

2. An impeller comprising, a hub having means for mounting for rotation about an axis, a plurality of blades fixed to the hub and extending longitudinally along a path generally lateral and normal to the hub axis; each of said blades being hollow and defining an inner cavity, each of said blades also having leading and first and second spaced trailing edges, said cavity extending substantially from the leading edges to the trailing edges, the blade cavities each being open to the ambient atmosphere through an aperture disposed between the first and the second trailing edge, each of said cavity apertures extending over substantially the entire extent of the fan blade.

3. An impeller comprising, a hub having means for mounting of rotation about an axis, a plurality of blades fixed to the hub and extending longitudinally along a path generally lateral and normal to the hub axis; each such blade comprising, first and second pitch contoured members, the members having a common leading edge and spaced trailing edges, said members defining a cavity therein open to the ambient atmosphere through an opening disposed between said trailing edges, and an end closure fixed to each member, the end closure defining an end of the cavity remote from said axis of rotation and at an end of said blade remote from said axis of rotation.

4. An impeller comprising, a hub having means for mounting for rotation about an axis, a plurality of blades fixed to the hub and extending longitudinally along a path generally lateral and normal to the hub axis; each such blade comprising, first and second pitch contoured members, the members each having a leading and a trailing edge, the leading edges being fixed together and the trailing edges spaced from one another to define a blade extension cavity extending substantially from the leading edges to the trailing edges and being of generally V-shaped cross section, each of said blade cavities extending substantially to the radial extremity of the blade.

5. An impeller comprising, a hub having means for mounting for rotation about an axis, a plurality of blades fixed to the hub and extending longitudinally along a path generally lateral and normal to the hub axis; each of said blades each having a transverse dimension at said trailing edge which is substantially the greatest blade transverse dimension in any given plane of cross section, each of said blades having first and second outer surfaces, each of the first surfaces being inwardly concave in cross section, the degree of concavity being greater as the plane of cross section is moved outwardly from the hub.

6. An air circulator comprising, a unidirectional motor having a drive shaft projecting therefrom, an impeller mounted on the shaft, said impeller comprising a hub mounted on the shaft and a plurality of laterally extending blades fixed to the hub, each of said blades having a leading edge and a trailing edge, each of said blades defining an internal cavity open to the atmosphere along said trailing edge, each of said cavities being substantially equal to the total volume defined by its blade, each of said blades having a cross section of increasing transverse dimension from the leading to the trailing edge, each of said blades having first and second outer surfaces extending from the leading to the trailing edge, and at least one of said surfaces of each of said blades being concave.

7. An air circulator comprising, a unidirectional motor having a drive shaft projecting therefrom, an impeller mounted on the shaft, said impeller comprising a hub mounted on the shaft and a plurality of laterally extending blades fixed to the hub, each of said blades hav- 5 ing a leading edge and a trailing edge, each of said blades defining an internal cavity open to the atmosphere along said trailing edge, each of said cavities being substantially equal to the total volume defined by its blade, each of said blades having a cross section of increasing transverse dimension from the leading to the mailing edge, each of said blades having first and second outer surfaces extending fnom the leading to the trailing edge, and one of said surfaces of each of said blades being concave and the other surface being substantially flat in a plane substantially normal to the axis of the shaft and the hub.

References Cited in the file of this patent UNITED STATES PATENTS Way Jan, 16, Nitschke July 17, Wells Nov. 6, Fischer May 17, Peterson June 13, Fogel July 30,

FOREIGN PATENTS Germany July 211, 

